Arock sample was placed in a strength-testing machine at a uniform confining force of 10,000 lbf and is compressed axially up to failure point. a force of 12,000 ibf was required for rock failure, and the cross- sectional area and the height of the sample were 2.0 sq in and 1.8 in respectively. the sample failed along a plane that marks a 350 angle with the direction of compressional loading a) construct the mohr's circle using the two principal stresses present b) compute the shear stress present along the plane of failure c) compute the normal stress to the plane of failure. d) compute the angle of internal friction. e) compute the cohesive resistance of the material. f)label the parameters computed in the previous four steps on the mohr's circle construction. using the mohr criterion, compute the compressional force required for rock failure if the sample is placed under a 5,000-psi confining pressure.